1. Field of the Invention
The present invention relates to an engine speed control apparatus for adjusting a rotating rate of an engine of a working vehicle, such as a lawn mower.
2. Description of the Related Art
Generally, an accelerating structure of a working vehicle has only a hand accelerator device, or both a hand accelerator device and a foot accelerator device.
In the former, a hand accelerator lever retainable in a selected position is set to a high speed position (usually a top speed position) for an operational run, and to a suitable low speed position for a non-operational run.
In the latter, an accelerator pedal is depressed to control engine speed with a hand accelerator lever set to a high speed position for an operational run, and with the hand accelerator lever set to an idling position or a selected low speed position for a non-operational run.
In the former having only the hand accelerator device, the hand accelerator lever must be set to different positions for the operational run and non-operational run. Since the shifting operation is troublesome, the operator often drives the vehicle in a non-operational run while leaving the hand accelerator lever set to the high speed position, resulting in a wasteful consumption of fuel and producing loud engine noise.
In the latter having both the hand accelerator device and foot accelerator device, the working vehicle may be driven in a non-operational run with the same feeling as when driving an ordinary automobile since acceleration or deceleration is effected by an extent to which the accelerator pedal is depressed to select a running speed through a transmission. However, to start an operational run, the hand accelerator lever must be set to a high speed position. In this case, as in the former, the operational run and non-operational run require a troublesome operation to shift the hand accelerator device from one position to another to change engine speed.